Wave 22 is when the game takes you to the next level of complexity. Tanks are mixed in with Enforcers.

The best strategy is the basic Tank strategy. Stay in the middle zone and fire in all directions to remove the flurry of Spheroids and Quarks before they generate Enforcers and Tanks.

You will need to fight the Tanks while avoiding touching the edges of the playfield where the shots from the Enforcers will finish you.

Wave 28 – Throw in some Tanks for good measure

Starting on this wave you will find a couple Quarks are thrown into each screen thereafter. They tend to not generate Tanks until later in the wave so aren’t an immediate threat.

But at this level of the game, the Quarks and Spheroids will zoom through the middle of the screen trying to get you at the start of a wave. Using a circular movement of the player at the start of a wave will give you a slight edge for offsetting the quick attack.

From this wave on, whenever grunts are mixed in on the screen- at start of wave, use a small circular movement to clear out the nearest grunts and avoid the zooming Spheroids/Quarks.

Then go into the circling herding technique through the middle phase of the wave. Be alert for a chance to take a stray shot to kill off any Tanks.

Grunt Cross Firing- (Master skill)

Grunts jump faster when running on diagonals, so especially at the start of a wave the player has better accuracy at hitting them when firing horizontally or vertically

Some players prefer to find a section of the screen where they can shoot across the screen horizontally and vertically to remove groups of enemies, at the early part of a wave.

The minimal movement of the player allows protection of the immediate play zone to quickly eradicate grunts, which frees up the player to gather humans and deal with enforcers and tanks.

Obviously, not an effective strategy later in the wave, when many Enforcers or Tanks are on the screen which will zero in on your location with projectiles.